def demo(obj):
    print("形参值：",obj)
    obj +=obj
    print("形参值：",obj)
#调用函数
print("=============值传递==============")
string = "这是第一个测试"
print("调用函数前实参值：",string)
demo(string)
print("调用函数前实参值：",string)
print("=============引用传递==============")
list1=['1','2','3','4']
print("调用函数前实参值：",list1)
demo(list1)
print("调用函数后实参值：",list1)